kildebrandt



2- Sheets-Sheet 1.

(No Model.)

B. s. HILDEBRANDT. BALANCED SLIDE VALVE.

Patented Nov. 1,1881.

' WITNESSES:

INVENTOR: 5%gfl 19 ATTORNEYS.

(No Model.) 2 Shets-Sheet 2.

E. S. HILDEBRANDT.

BALANCED SLIDE VALVE.

No. 249,045. Patented Nov. 1,1-881.

' ATTORNEYS.

EYERS. flhmouma m mr. Wilhmglull. u. c.

NITED STATES PATENT OFFICE.

EDWIN S. HILDEBRANDT, OF BALTIMORE, MARYLAND, ASSIGNOB OF ONE. HALF TO FRANK M. HILDEBRANDT, OF SAME PLACE.

BALANCED SLIDE-VALVE.

SPECIFICATION forming part of Letters Patent No. 249,045, dated November 1, 1881.

Application filed March 24, 1881. (No model.)

with the cover B for the valve also removed.-

Fig. 3 is a vertical section through the line to w of Fig. 1. Fig. 4 is a vertical section through 1 the line or a: of Fig. 1. Fig. 5 is a vertical section through the line 51 y of Fig. 2. Fig. 6 is a plan view of a modification with the cover B removed. Fig. 7 is a vertical section of the same through the line 2 z.

My invention relates to an improved balanced slide-valve for steam-engines; and it consists in providing the slide-valve with a stationary cover, under which the valve moves, and then providing a marginal frame for the 2 5 top edge of the valve, which is lifted by a system of crossed levers, either through the pressure of steam or by a weight, to force the marginal frame up against the stationary cover and form always a tight joint between the 0 valve and its cover to compensate for wear.

The invention also consists in forming an elongated hole in the stationary cover above the valve and placing a plunger therein, whose top area is exposed to the steam in the valvebox, and is about equal to the steam-area of the valve over its ports below, and which flange rests upon the top of the valve to neutralize the upward pressure of the steam in its ports and balance the valve.

In the drawings, A represents the outer casing of the valve-box, which is bolted down upon the top of the cylinder above the induction-ports a a and exhaust-port b.

Rigidly fixed within the valve-box is a top 5 plate or cover, B, which fits down closely upon the slide-valve to cover the same and exclude steam-pressure from the upper surface of the valve except at a given point, as hereinafter described.

0 is the valve, which has a D-shaped openmg underneath the same, that alternately covers two of the pol ts, and to which valve a rod, D, is attached by a head, (I, which is slipped into a seat on the valve, and thence emerges from the valve-box through. a stuffing-box.

In the top plate or cover B for the valve is formed an elongated rectangular opening, Fig.

1, whose length is at right angles to the line of movement of the valve. In this opening is placed a corresponding-shaped plunger, F, 6 whose upper surface appears through the cover and is exposed to steam-pressure, and whose lower surface rests upon elevations e e on the valve, Figs. 3 and 4, so that the pressure of steam on the top of this plungeris transmitted to the valve. The area of this steam-exposed surface of plunger F is so relatively propor tioned to the area of the ports below as to cause the downward pressure on the plunger to exactly balance the upward pressure of the 0 steam from the ports, thus making a balanced valve.

As the valve slides beneath the cover B, the continuous wear would eventually make a loose joint between the valves and cover that would 7 leak steam so as to destroy the balanced character of the valve. To obviate this I place over the upper edges of the valve a marginal frame, E, which has a rabbeted lower edge, that permits it to rise and fall about the edges of the valve without parting from the same. This marginal frame I cause to be lifted up against the top plate, B, by a constant pressure, so that as the valve wears loose between the upper and lower walls of its chamber the marginal frame will rise and always preserve a tight joint at the top edges of the valve. For securing the result of constantly pressing this frame upward I fulcrum to an elevated support at each end of the valve. a pair of 0 crossed levers, H H. The lower ends of these levers rest beneath the edges of the marginal frame E, while their upper ends carry pins f, that rest in the opposite ends of bars I I, one at each end of the valve, so that by depressing these bars the marginal frame is raised and a tight joint maintained. For depressing these bars I employ in the cover B steam-plungers J J, Figs. 1 and 4, which have a relatively small area exposed for steam-pressure at the upper surface of the cover, and whose lower surfaces rest upon the bars I, so that the pressure of steam in the valve-box constantly serves to hold the marginal frame up. As a modification of this part of my invention I may substitute for these steam-plungers J a weight, K, as shown in Figs. 6 and 7, which would serve the same purpose, and when I use such a weight I cause it to be sustained upon the pins fat the tops of the crossed levers and dispense with bars I. I also prefer in this modification to make the top plate, B, imperforate, as shown in Figs. 6 and 7, and balance the upward pressure of the steam in the ports by flanges at the lower edges of the valve, in the usual way.

. \Vith respect to the marginal ring which is pressed upwardly to make a tight joint at the upper surface of the valve, this I do not claim, broadly, but onlyits combination with the devices shown and described.

Having thus described my invention, what I claim as new is- 1. The combination, with a slide-valve, of a stationary cover for the same, a marginal frame surrounding the upper edge of the valve, a system of crossed levers for lifting said marginal frame, and one or more steam-plungers or their equivalent, as described, for pressing upon said crossed levers and lifting said marginal frame, as set forth.

2. The combination, with a slide-valve, of a stationary cover for the same, having an opening in it and a piston resting in said opening, and having its upper surface exposed to cause the downward steam-pressure to neutralize or balance the upward pressure of the steam in the ports, as described.

3. The combination, with a slide-valve, ofa stationary cover for the same, provided with openings, a balancing-plunger, F, resting upon the valve direct, the independent plungers J J, the crossed levers, and the marginal frame resting about the upper edge of the valve and raised through the crossed levers and plungers J, substantially as shown and described.

E. S. HILDEBRANDT.

Witnesses EDWD. W. BYRN, SOLON C. KEMON. 

